Little bit of sweat may help seniors stave off dementia

Even moderate exercise can delay dementia for many older adults, and the frailest may benefit most, according to a new study led by Seattle researchers.

In fact, just 15 minutes of exercise — such as walking or swimming — three times a week can reduce the risk of Alzheimer's disease or other dementia by 30 to 40 percent, the researchers report in one of the largest, most definitive studies to date on the relationship between dementia and exercise.

"What is striking is that it didn't take much to reduce the risk. ... If you don't exercise, you should start. It's never too late," said Dr. Eric Larson, director of Group Health Cooperative's Center for Health Studies and leader of the study on exercise by Group Health and the University of Washington.

Larson and his colleagues said they found that the weakest patients, who did little or no exercise, could cut their chances of dementia the most if they began to exercise.

"If these findings are confirmed, senior citizens may have more reason to 'use it even after you are losing it,' " the scientists said in today's edition of the Annals of Internal Medicine.

Besides walking or swimming, participants in the study also did bicycling, aerobics, weight training, stretching and other exercises.

The study didn't account for the intensity of exercise, only the frequency.

The researchers tracked 1,740 Group Health members 65 and older for about six years. Out of the original pool, 1,185 people were later found to be free of dementia, and 77 percent of them reported exercising three or more times a week; 158 people showed signs of dementia, and only 67 percent of them said they exercised that much. The rest either died or withdrew from the study.

The frequency of dementia was 13 per 1,000 person years for those who said they exercised three or more times a week, compared with 19.7 per 1,000 person years for those who reported exercising less.

Several previous studies on the relationship between exercise and dementia have conflicted. Some link exercise to reducing dementia risk, while others have found no such relationship. Scientists speculate that may be because people in the earliest, undetected stages of dementia often stop exercising.

In the Seattle research, participants were tested to make sure they were not already suffering from early dementia. The results also considered several other factors that could affect whether someone develops dementia, including alcohol use, smoking, dietary supplements, education, diabetes, heart disease, depression and a certain genetic predisposition to Alzheimer's.

Polls have shown that of all the afflictions of aging, many people fear Alzheimer's the most. Experts estimate 4.5 million Americans have the disease, and its prevalence is expected to grow as the population continues to age.

Exercise may delay dementia because it stimulates blood flow to the brain, Larson said. Other recent research shows that older people who are physically fit have the least damage to the area of the brain that is first affected by Alzheimer's.

The Seattle scientists said their study may have been limited by the fact that most participants were white, and their nonleisure or work activities were not considered. More research is needed, including investigating how different amounts of exercise may affect when dementia begins.

Other researchers said randomized studies — in which participants would be randomly assigned to either exercise or maintain their usual habits — are needed to confirm the findings.

Bill Thies, vice president for medical and scientific affairs for the Alzheimer's Association, said a randomized trial with more people could help answer questions such as what types of exercise might help more than others.

For older adults who exercise regularly, the benefits seem obvious.

"I'm a better thinker because I have a better body. I really believe that," said Laura Pizzuto, a 78-year-old Seattle artist who has exercised regularly since her college days, when she took dance classes.

Pizzuto's regimen has run the gamut. She stretches like a dancer. She was a runner for 35 years. She hiked and backpacked through the Cascades for decades. She even did yoga in bed after recent foot surgery. Now she exercises for an hour three times a week in a Group Health program for seniors.

"There's this certain energy in the group, and of course I love to move," she said.

Exercise helps her focus mentally and physically on painting, she said. Recently, it helped her through the grief from the death of her husband of 54 years. She reads a lot and writes about her loss and her life.

"It is profound," she said. "It gives me a base for my life."

Warren King: 206-464-2247 or wking@seattletimes.com

The Associated Press contributed to this report.